Relationship between Electronic and Geometric Structures of the O/Cu(001) System

TL;DR

This study uses first-principles calculations to analyze how oxygen atoms influence the electronic and geometric structures of the O/Cu(001) system, revealing the importance of Coulomb interactions in surface structure formation.

Contribution

It provides a detailed first-principles analysis of the electronic structure and Coulomb effects in the O/Cu(001) system, highlighting differences between phases.

Findings

Oxygen perturbs local electronic potentials and subbands.

The (2√2×√2)R45° phase has weaker perturbation than c(2x2).

Long-range Coulomb interactions drive surface structure formation.

Abstract

The electronic structure of the $(2\sqrt{2}\times\sqrt{2})R45^{\circ}$ O/Cu(001) system has been calculated using locally self-consistent, real space multiple scattering technique based on first principles. Oxygen atoms are found to perturb differentially the long-range Madelung potentials, and hence the local electronic subbands at neighboring Cu sites. As a result the hybridization of the oxygen electronic states with those of its neighbors leads to bonding of varying ionic and covalent mix. Comparison of results with those for the c(2x2) overlayer shows that the perturbation is much stronger and the Coulomb lattice energy much higher for it than for the $(2\sqrt{2}\times\sqrt{2})R45^{\circ}$ phase. The main driving force for the 0.5ML oxygen surface structure formation on Cu(001) is thus the long-range Coulomb interaction which also controls the charge transfer and chemical binding in the system.